Usage: shasum [OPTION]... [FILE]... Print or check SHA checksums. With no FILE, or when FILE is -, read standard input. -a, --algorithm 1 (default), 224, 256, 384, 512, 512224, 512256 -b, --binary read in binary mode -c, --check read SHA sums from the FILEs and check them -t, --text read in text mode (default) -U, --UNIVERSAL read in Universal Newlines mode produces same digest on Windows/Unix/Mac -0, --01 read in BITS mode ASCII '0' interpreted as 0-bit, ASCII '1' interpreted as 1-bit, all other characters ignored -p, --portable read in portable mode (to be deprecated) The following two options are useful only when verifying checksums: -s, --status don't output anything, status code shows success -w, --warn warn about improperly formatted checksum lines -h, --help display this help and exit -v, --version output version information and exit When verifying SHA-512/224 or SHA-512/256 checksums, indicate the algorithm explicitly using the -a option, e.g. shasum -a 512224 -c checksumfile The sums are computed as described in FIPS PUB 180-4. When checking, the input should be a former output of this program. The default mode is to print a line with checksum, a character indicating type (`*' for binary, ` ' for text, `U' for UNIVERSAL, `^' for BITS, `?' for portable), and name for each FILE. Report shasum bugs to email@example.com
The following command shows how to compute digests for typical inputs such as the NIST test vector ``abc'':
perl -e "print qq(abc)" | shasum
Or, if you want to use SHA-256 instead of the default SHA-1, simply say:
perl -e "print qq(abc)" | shasum -a 256
Since shasum mimics the behavior of the combined GNU sha1sum, sha224sum, sha256sum, sha384sum, and sha512sum programs, you can install this script as a convenient drop-in replacement.
Unlike the GNU programs, shasum encompasses the full SHA standard by allowing partial-byte inputs. This is accomplished through the BITS option (-0). The following example computes the SHA-224 digest of the 7-bit message 0001100:
perl -e "print qq(0001100)" | shasum -0 -a 224